The makers of the bestselling video game GrandTheft Auto are being sued for more than £60m (read: $100 million USD) after two teenagers said they were copying its violent scenes when they killed a man.

The court case could help to decide the debate over whether violent video and computer games cause aggression in children. GrandTheft Auto and its three sequels are designed in Britain (read: Scotland, all hail the king) and have topped the UK and US games charts, selling more than 20 million copies in the past five years. The player acts the role of a street thug with 40 different weapons.

Points, ammunition and more weapons are awarded for completing missions that include stealing cars, crashing them, shooting pedestrians and other motorists, drug dealing and beating up prostitutes. The fourth in the series, GrandTheftAuto:ViceCity, quickly became the bestselling video game in history when it was launched last year, with 250,000 copies sold in the first two days. (In England)

The two boys told police they shot at vehicles on a highway near their home with a .22 rifle in an attempt to recreate images from GrandTheft Auto. Mr Hamel, a nurse, was killed while driving home to Knoxville, Tennessee. Miss Bede, who was travelling in another car with her boyfriend, was seriously injured and has eight fragments of shrapnel in her pelvis.

The Buckner brothers had no criminal record or any history of trouble-making. In court last month, they pleaded guilty to reckless homicide, aggravated assault and reckless endangerment. They were sentenced to indefinite detention. District Attorney General Al Schmutzer told the court: "They said they got the idea from a video game called GrandTheft Auto and that they were bored, that they went out and began shooting."

In a letter to victims and their families, Joshua said: "I did not mean to hurt anyone. I hate that it happened. This will stick with me for the rest of my life."

Miss Bede and the family of Aaron Hamel plan to sue Take-Two Interactive Software, which publishes GrandTheft Auto, for liability in a wrongful death lawsuit. Take-Two owns Rockstar Games, which is based in Edinburgh and designed the first version of the game in 1997. Sony will also be named in the lawsuit, because GrandTheft Auto was made exclusively for its Play- Station consoles. Sony declined to comment on the case.

Jack Thompson, the lawyer representing the families, said the court case could be the first to rule on whether watching and playing violent video games caused excess aggression in children. He said: "We are going to show that this game did influence these boys and cause them to go out and shoot at these people.

"There has been a wealth of research to show that children's brains process these video games in a different way from adults'. They cannot differentiate between fantasy and reality, so they play these games and then think if they do the same thing in reality, it's OK, there will be no consequences."

Referring to The Manchurian Candidate, a 1962 film in which American soldiers are brainwashed into becoming fighting machines in the Korean war, Mr Thompson said: "We have got a nation of Manchurian Candidates who are training on these video games." Mr Thompson plans to call American defence ministry officials to give evidence on how they have employed video-game designers to help to train soldiers.

One company, Pandemic Games, is selling a game to the public that was designed to train infantry troops in urban combat. Players use "real weaponry and equipment currently in use by the US Army".

Mr Thompson claims that this shows video games "desensitise" people, particularly children, to violence. He will also point to the Columbine High School massacre in Colorado in 1999, when Eric Harris and Dylan Klebold shot 13 people dead. Both boys were fans of the video game Doom, which has been used to train US soldiers in lethal combat.

Claims of a link between video games and real violence have always been highly controversial, with manufacturers pointing out that millions of people enjoy playing the games but do not show any aggression. There are also arguments over whether aggression is innate, or learnt, and whether people who are naturally more aggressive are more likely to play violent video games.

But recent research has tended to back the argument that games can increase the risk of some young men committing acts of aggression.

A study by Iowa State University showed last year that even brief exposure to violent video games could temporarily increase aggressive behaviour in all types of people. Another study found that people who had played violent video games were more likely to have aggressive attitudes.

Craig Anderson, who led the studies, said: "The active nature of the learning environment of the video game suggests this medium is potentially more dangerous than television and movie media. With the recent trend toward greater realism and more graphic violence in video games, consumers and parents of consumers should be aware of these potential risks."

GrandTheft Auto has an 18 certificate in Britain but is popular with much younger teenagers, especially boys.

Yeah, Rockstar should counter sue the parents for "One Billion Dollars" because they allowed their 14 and 16 year old kids to play a game that was rated Mature, when they clearly didn't have the mental capacity to do so.